Window-envelop



Wl E. SWIFT.

WINDOW ENVELOP.

APPLICATION HLED MAR. 2s. 1918.

Patented Aug. 23, 1921.

nveno v UNITED STATES ArA-irilrrl ori-ica WILLAIBD E. SWIFT, 0F WORCESTER, MASSACHUSETTS, ASSIGNOR TO UNITIEIlLfgTATII'B ENVELOPE COMPANY, OF SPRINGFIELD, MASSACHUSETTS, A CORPORATION OF MAINE.

Specification of Letters lPatent. Patented Aug. '1921.

riglnal application tiled Iarch 2, 1915, Serial No. 11,574. Divided and this application med Iarch 28, 1918. Serial No. 225,216.

y To all 'whom t may concern.'

Be it known that I, WILLAim E. Swir'r, a citizen of the United States, residing at Worcester, in the county of Worcester and Commonwealth of Massachusetts, have invented a new and useful Improvement in. a Window-Envelo of which the following, together with t e accompanying drawings,

` is `a specification.

The present invention' relates to window envelops of the two-piece type, namely those characterized by a substantiall transparent patch secured within the insi e of the en' velo and covering an opening formed in the ront side of the same. The present application is a division of my allowed application Serial No. 11,574, filed March 2, 1915, for a process of making envelops.

The material commonly used for such patches is commercially known as glacine paper; the same possesses a considerable degree of transparency, which ylends itself peculiarly to the manufacture of such envelops. The present invention is concerned with the production of an envelop of this type in which the window, or transparent patch, is made to possess a greater degree of transparency than is possessed by the windows of such envelops now in ordinary use; the features of said invention are set forth in the following description and pointed out in the annexed claims, reference being had to the accompanying drawings, in which- Figure 1 represents a View of the rear or inner side of an envelop blank, suitable for the application of my invention thereto, and

Fig. 2 represents a front view of a completed envelop embodying my invention and made in accordance with the method which forms a part of-the same.

Similar reference characters refer to similar parts in both figures.

The shape of the envelop to which my 1nvention is applied is immaterial; the envelop shown in' the drawings, which is illustrative merely, is made fronr a blank h aving a body portion 1, forming the front side of the completed envelop, side or end flaps 2 and 3 which are folded inwardly to form the back side of the envelop, a bottom flap 4:, and a closure Hap 5. The body portion 1 has a suitably disposed elongated opening 6 therein, which is covered by a patch 7 of transparent or glacine aper, said patch being somewhat larger tllian said opening and overlapping the edges of the same in all directions, being secured to the gummed o r top side of the blank by adhesive material, indicated at 8, which surrounds said opening, so that the blank when folded in the ordinary manner, 'provides an envelop having a transparent coverin for the opening in its front side, whic covering or patch is attached upon the inside of the envelop.

The glacine paper ordinarily used as the material for such patches differs widely) in composition and texture from ordinary opaque or semi-opaque paper; the glacine paper is close-knit, by reason of the preponderance of cellulose matter in the composition thereof, and moreover, said paper presents a smooth, hard and relatively 1mpenetrable surface, quite unlike the nap-like surface of ordinary paper. The cellulose character of the material gives it its transparent quality; however, I have discovered that the degree of such transparency may be very considerably increased by the treatment of one or both surfaces with a liquid, such as varnish, or other substantially transparent liquid haying resinous or other transparent matter in solution.

I am aware that window envelops have been made heretofore by applying oleaginous substances, in liquid form, to a space upon the front or address side of the envelops torender the same transparent, and I make no claim to this method of manufacture, nor to the article produced thereby. In all such prior processes, the production of a transparent panel depends upon the passage of the liquid through the paper from one surface to the other; the adaptability of most commercial grades of paper, from whichenvelops are made, to `this .treatment, by reason of the loosely-knit, coarseibered composition of the material and the villous, nap-like character of the surface thereof, is well recognized. The action is essentially one of permeation, and as a consequence the greater portion of the liquid is completely removed and isolated'from the drying action of the atmosphere, the evaporation of the liquid is practically never com- .p1eted, and the window or panel, while possessing ,a certain limiteddegree o f transparency, invariably is of an oily sticky nature on both sides and is never thoroughly In carrying out my invention, the transparent glacine patch 7 is applied to the opening 6 in the envelop blank in the usual manner; in some cases the reverse surface of the patch, i. e., the surface which is not brought into contact with the adhesive 8 surrounding the opening, may already have received a coating of the transparent liquid above referred to, either before or after being cut into patch form. Or, obviously, the coating of trans arent liquid may be applied to this sur ace of the patch after the latter has been secured over the opening in the blank, by any suitable means, such as a brush, ora die, or a roller coated with the liquid. Preferably, a solution having the property of drying quickly is used; but I do not wish to confine myself tothe use of such a solution, since it is manifest that the character of the paper itself, by reason of 1 ts impenetrability is` conducive to therapid drying of the liquid, since sald liquld lies on the surface ofthe paper in a thin film, completely exposed to the evaporative action of the air. Consequently, there is no impairment of the adhesive qualities of the other surface of the patch since there is absolutely no permeation of the liquid to said other surface torender the same oily, and\ thereby unsuitable for contact with the glue 8. f'

Irrespective of whether or not thls treatment of the reverse surface of the patch is afforded, the blank, with the patch applled thereto is now in condition for folding, and in condition for the treatment of Vthat surface of the patch lying on the address or front side of the envelop, either before or after the folding of the blank to form a completed envelop, Fig. 2. This latter step involves the subjection of the successively fed blanks, or envelops, as the case may be, to the action of a suitable coating device or die, corresponding in shape to, but slightly smaller than the opening 6 in the address side of the envelop; said die prints or lays a film of the varnish or other transparent liquid upon the outer surface of the atc-h, preferably just within the edges o said opening 6, as indicated by the broken line 9, Fig. 2. The advantages accruing from the treatment of the patch in this manner have already been set forth; the transparency of the patch is materially increased, the liquid dries rapidly, owing to its complete exposure to the air, and there is no permeation Such application,

of said liquid to the reverse side ofjthe patch, necessitating a drying of this side before the blankls folded, or, if -already folded, necessitating a delay in stacking the completed envelops to allow the patches of the same to dr On the contrary, the envelops are ready for instant use as soon as the/short time required for the evaporation of the thin film of thereof has elapsed. i

I am aware that it has been proposed to render a semitransparent paper, known as glacine paper, more transparent by the application of a rapidly drylng resinous solution to its surface, and to use the same for covering the Window opening of an-outlook envelo and I do not claim such broadly.

however, is liable to interfere with the application of an adhesive material to the surface so treated. I overcome this objection inthe construction of a window envelop by treating the inner side only of a s emltransparent patch prior to its application to the body of the envelop by adhesive material, and after the patch has adhered to the body of the envelop, I treat the outer surface of the patch within the limits of the window opening with a rapidly drying resinous solution, preferably. by means of a die corresponding in shape and size to the window opening. By the above construction, I increase the transparency of the patch without interfering with the adhesion of the patch to the body of the envelop.

I cla1m,

1. As an article of manufacture, an envelo? provided with a Window opening in its ace and having a margin of adhesive material around said opening, said opening and said margin being covered by a patch of semitransparent material, with a transparent solution applied to the outer surface of said patch but wholly within the limits of said o ening.

2. s an article of manufacture, the combination with an envelop provided with a Window opening in its face and having a gummed margin around said opening, of a patch on the inner side of the envelop covermg said opening and said gummed margin, with the side of the patch opposite said gummed margin treated to a transparent solution and with the outer side of said patch treated to a similar solution but Wholly within said openin Dated this 22nd day of larch, 1918.

WILLARD E. SWIFT.

Witnesses:

NELLIE WHALEN, Gao. H. KENNEDY, Jr.

liquid on the front sides 

